Lifestyle, genes, and cancer

Baseline knowledge and receptiveness to genetic testing for hereditary breast and ovarian cancer syndromes in Chinese high-risk females

Limited studies have examined the pre-counselling knowledge and attitudes of high-risk women on hereditary breast and ovarian cancer (HBOC) syndromes genetic screening in Asia Pacific regions, particularly among Chinese. After controlling cost, an intrinsic barrier to undertake such screening, comprehensive understanding of the baseline characteristics of this cohort towards HBOC genetic counselling and testing service (GT) could be sought. This study aimed at exploring the baseline knowledge, possible motivators, barriers, and decisional factors of undertaking such service. One hundred and forty-two Southern Hong Kong Chinese high-risk females (89.4% with cancer history; 10.6% were cancer-free at-risk family members) completed a questionnaire right before their pre-testing GT. Results showed that perceived benefits to self and family members with reference to cancer prevention are important decisional motivators. A sponsored cancer genetic testing service in this cohort was crucial as 71.3% would not have opted for self-financed screening. Pre-testing and post-testing counselling were essential, particularly for older and less educated high-risk individuals. More importantly, after thorough pre-counselling with Q&A session, the entire cohort in this study gave written consent to undertake GT. Moreover, those proven to be germline pathogenic variant carriers were willing to share the information with family members and successfully persuaded them to pursue GT.

Body mass index, physical activity, and physical fitness of adolescence

Background: Adolescents experience growth and significant changes in body composition which influence physical activity and response to sport or exercise. The level of physical fitness in adolescent girls is usually lower than that of boys, due to differences in body composition and levels of physical activity. The aim of this study was to examine the relationship between fat mass percentage, body composition, physical activity, and physical fitness.

Design and Methods: This study used an analytical observational, and cross-sectional design with total samples consisting of 70 male and female students aged 14-15 years. They were selected through simple random sampling, and the data collected were anthropometric measurements, body composition, physical activity and physical fitness. In addition, the Pearson correlation test was used for data analysis.

Results: The results showed that 68.57% of participants had a normal body mass index, 74.3% had moderate physical activity, and 44.28% had fat mass percentage including an obesity category and, 54.29% had low physical fitness. Furthermore, the Pearson test showed a significant relationship between physical activity, body mass index and fat mass percentage with physical fitness.

Conclusions: An increased fat mass percentage is associated with decreased levels of physical fitness. Furthermore, a good determinant of low physical fitness in obese conditions is the percentage of fat mass rather than BMI.

Cancer Incidence Trends From 1999 to 2015 And Contributions Of Various Cancer Types To The Overall Burden: Projections To 2030 And Extrapolation Of Economic Burden In Saudi Arabia

Background

Cancer incidence in Saudi Arabia has increased for the last two decades, ratcheting up to global levels. The study aimed to analyze cancer trends and the contributions of various cancer types, forecast incidence, and estimate the economic burden in 2030.

Methods

A national-level cohort study utilizing the Data of Cancer Registry of patients who were diagnosed in 1999–2015. New cases in 2016–2030 were forecast and predicted based on 1999–2015 data. We used growth assumption and regression analysis to predict the trends of cancer cases. We assessed the contributions of cancer types to incidence trends. We carried forecasting of new cases and extrapolation of the potential economic burden. We conducted a sensitivity analysis of the cost of cancer with respect to changes in economic and epidemiologic factors.

Results

The findings suggest that the number of known cancer cases increased by 136% from 1999 to 2015 and is projected to rise by 63% in 2030. The forecast indicates female cases will account for higher number of cases and greater proportion increase. The future cost of all cancer types would be estimated at $7.91 billion in 2015 value, of which $3.76 billion will be attributable to care management and $4.15 billion in lost productivity. With the assumption of growth of the aged-standardized incidence rate, the costs of care management and lost productivity are projected to be $5.85 and $6.47 billion, respectively in 2030, an increase of 56% in each component. The future undiscounted total estimated economic burden for the period 2015–2030 would be $159.44 billion, of which 47.5% will be attributable to care management. Estimates were robust to uncertainty, but the 5-year prevalence of cancer survivorship would account for the greatest variability.

Conclusion

Our model showed an upsurge of cancer burden in terms of incidence and the potential economic burden, which may inform cancer control measures.

The possibility of lifestyle and biological risk markers to predict morbidity and mortality in a cohort of young men after 26 years follow-up

OBJECTIVES

To study the association between lifestyle and biological risk markers measured at one occasion, morbidity and mortality from cardiovascular disease (CVD) and cancer, and morbidity from diabetes approximately 26 years later.

DESIGN

A follow-up study of a cohort of men, 33-42 years old at baseline.

SETTING

Primary healthcare centre in Sweden.

PARTICIPANTS

All 757 men, living in the community of Habo in Sweden in 1985, and all 652 of these participating in a health examination in 1985-1987.

INTERVENTIONS

Health profile and a health dialogue with a nurse. A doctor invited the high-risk group to further dialogue and examination. Intervention programmes were carried out in the primary healthcare centre and in cooperation with local associations.

MAIN OUTCOME MEASURES

CVD and cancer diagnoses from the Swedish National Board of Health and Welfare. Data from pharmacy registers of sold drugs concerning diabetes mellitus.

RESULTS

The participants were divided in three groups based on summarised risk points from lifestyle (smoking, physical activity, alcohol consumption) and biological risk markers (body mass index (BMI), blood pressure, serum cholesterol) selected from the health profile. Comparisons were done between these groups. The group with the lowest summarised total risk points had a significantly lower risk for CVD and cancer compared with the group with the highest summarised risk points. The group with the lowest risk points concerning lifestyle had a significantly lower risk for CVD, and the group with lowest risk points for biological risk markers had a significantly lower risk for both CVD and cancer compared with the groups with the highest risk points. Smoking and serum cholesterol were the most important risk factors. In association to diabetes, BMI and smoking were the most important risk factors.

CONCLUSIONS

Risk factors measured on one occasion seemed to be able to predict CVD, cancer and diabetes 26 years later.

100 years Lynch syndrome: what have we learned about psychosocial issues?

In the care of patients with Lynch Syndrome (LS), a range of psychosocial issues are encountered, which significantly affect patient outcomes. A brief historical background of 'psycho-onco-genetics' (the domain where psychology, oncology and genetics meet) in relation to LS is presented, followed by an overview of important psychosocial issues identified in the past 20 years. The identification of mismatch repair genes in 1993-1994 made possible genetic counseling and testing for patients who had cancer and for potentially high-risk relatives without cancer. At that time, concerns were raised about the potentially negative psychosocial impact of predictive genetic testing. Since 1993, a large number of studies have been conducted to investigate the possible psychosocial benefits and limitations of such testing. This article presents an overview of: the uptake of and motivations for genetic testing, its psychosocial impact (e.g. psychological adaptation, impact on risk perception and self-concept, and concerns about, and experiences of, genetic discrimination), psychological screening instruments, adherence to and decision-making about preventive strategies, family communication, lifestyle changes, reproductive technology utilization, and professional psychosocial support needs of members of families with LS. Finally, challenges for the future are discussed, including population screening and genomic testing.

Tumor necrosis factor-α-induced a disintegrin and metalloprotease 10 increases apoptosis resistance in prostate cancer cells

In developed countries, prostate cancer (PCa) is the second most frequently diagnosed type of cancer and the third most common cause of cancer-related mortality in males. Compared with western countries, the morbidity rate of PCa in China is markedly lower, however, it is rising annually. The etiology of PCa is unclear, therefore, to investigate how a disintegrin and metalloprotease 10 (ADAM10) functions in PCa, ADAM10 mRNA and protein levels induced by tumor necrosis factor (TNF)-α were identified using polymerase chain reaction and flow cytometry, respectively. To investigate the mechanism of ADAM10 activity in PCa, specific inhibitors were used, and DNA transfection and RNA interference technology were employed to identify the interaction between ADAM10 and the Fas ligand (L). The results indicated that TNF-α induced ADAM10 expression in a time- and dose-dependent manner through the p38 mitogen-activated protein kinase/necrosis factor-κB signaling pathway. ADAM10 hydrolyzed FasL and contributed to apoptosis resistance of the tumor cells. These observations indicate a promising therapeutic modality for the treatment of apoptosis-resistant PCa, by targeting ADAM10 sheddase activity.

CanPrevent: a telephone-delivered intervention to reduce multiple behavioural risk factors for colorectal cancer

BACKGROUND

This pilot study aimed to test the acceptability and short-term effectiveness of a telephone-delivered multiple health behaviour change intervention for relatives of colorectal cancer survivors.

METHODS

A community-based sample of 22 first-degree relatives of colorectal cancer survivors were recruited via a media release. Data were collected at baseline and at six weeks (post-intervention). Outcome measures included health behaviours (physical activity, television viewing, diet, alcohol, body mass index, waist circumference and smoking), health-related quality of life (Short Form-36) and perceived colorectal cancer risk. Intervention satisfaction levels were also measured. The intervention included six telephone health coaching sessions, a participant handbook and a pedometer. It focused on behavioural risk factors for colorectal cancer [physical activity, diet (red and processed meat consumption, fruit and vegetable intake), alcohol, weight management and smoking], and colorectal cancer risk.

RESULTS

From baseline to six weeks, improvements were observed for minutes moderate-vigorous physical activity (150.7 minutes), processed meat intake (-1.2 serves/week), vegetable intake (1 serve/day), alcohol intake (-0.4 standard drinks/day), body mass index (-1.4 kg/m2), and waist circumference (-5.1 cm). Improvements were also observed for physical (3.3) and mental (4.4) health-related quality of life. Further, compared with baseline, participants were more likely to meet Australian recommendations post-intervention for: moderate-vigorous physical activity (27.3 vs 59.1%); fruit intake (68.2 vs 81.8%); vegetable intake (4.6 vs 18.2%); alcohol consumption (59.1 vs 72.7%); body mass index (31.8 vs 45.5%) and waist circumference (18.2 vs 27.3%). At six weeks participants were more likely to believe a diagnosis of CRC was related to family history, and there was a decrease in their perceived risk of developing CRC in their lifetime following participation in CanPrevent. The intervention retention rate was 100%, participants reported that it was highly acceptable and they would recommend it to others at risk of colorectal cancer.

CONCLUSIONS

Positive behaviour change achieved through this intervention approach has the potential to impact on the progression of CRC and other cancers or chronic diseases. A large scale randomised controlled trial is required to confirm the positive results of this acceptability and short-term effectiveness study.

TRIAL REGISTRATION

ACTRN12612000516886.

Incidence and predictors of all-cause and site-specific cancer in type 2 diabetes: the Fremantle Diabetes Study

OBJECTIVE

To explore the relationship between diabetes and cancer.

DESIGN

The Fremantle Diabetes Study (FDS) was a community-based longitudinal observational study of 1426 subjects, 1294 of which had type 2 diabetes.

METHODS

The FDS type 2 cohort and four age-, sex- and postcode-matched controls per case were followed for cancer events from 1993 until mid-2010 and incidence rate ratios (IRRs) were calculated. Competing risks proportional hazards models generated risk factors for incident cancers in the diabetic group.

RESULTS

There were 309 first cancers over 13 051 patient-years, or 2368 (95% confidence interval (95% CI) 2111-2647)/100 000 patient-years in the diabetes patients vs 1131 over 60 324 patient-years (1875 (1769-1987)/100 000 patient-years) in the controls. For those aged ≥45 years, the risk of all-cause cancer was elevated in type 2 diabetic men (IRRs 1.23, 95% CI 1.04-1.45) and women (1.30, 1.06-1.59). The incidence of colorectal cancer was increased (1.36, 1.01-1.82), especially in diabetic men aged 75-84 years (2.14, 1.22-3.64). Age at diabetes diagnosis (sub-hazard ratio 1.05, 1.02-1.09), calcium channel blocker therapy (2.37, 1.39-4.06), recent exercise (2.11, 1.06-4.20) and serum total cholesterol (0.68, 0.52-0.88) increased colorectal cancer risk. Pancreatic cancer was also more frequent in the diabetic patients (IRR 2.26, 1.20-4.10). Diabetic men and women had similar risks of prostate and breast cancer to those of controls (0.83, 0.59-1.14 and 0.86, 0.52-1.36).

CONCLUSIONS

Type 2 diabetes is associated with a moderately increased cancer risk in well-characterised community-based patients, especially pancreatic cancer and colorectal cancer in older men. Recommended cancer screening should be considered as part of routine diabetes management.

Quantifying mediating effects of endogenous estrogen and insulin in the relation between obesity, alcohol consumption, and breast cancer

BACKGROUND

Increased exposure to endogenous estrogen and/or insulin may partly explain the relationship of obesity, physical inactivity, and alcohol consumption and postmenopausal breast cancer. However, these potential mediating effects have not been formally quantified in a survival analysis setting.

METHODS

We combined data from two case-cohort studies based in the Women's Health Initiative-Observational Study with serum estradiol levels, one of which also had insulin levels. A total of 1,601 women (601 cases) aged 50 to 79 years who were not using hormone therapy at enrollment were included. Mediating effects were estimated by applying a new method based on the additive hazard model.

RESULTS

A five-unit increase in body mass index (BMI) was associated with 50.0 [95% confidence interval (CI), 23.2-76.6] extra cases per 100,000 women at-risk per year. Of these, 23.8% (95% CI, 2.9-68.4) could be attributed to estradiol and 65.8% (95% CI, 13.6-273.3) through insulin pathways. The mediating effect of estradiol was greater (48.8%; 95% CI, 18.8-161.1) for BMI when restricted to estrogen receptor positive (ER(+)) cases. Consuming 7+ drinks/wk compared with abstinence was associated with 164.9 (95% CI, 45.8-284.9) breast cancer cases per 100,000, but no significant contribution from estradiol was found. The effect of alcohol on breast cancer was restricted to ER(+) breast cancers.

CONCLUSIONS

The relation of BMI with breast cancer was partly mediated through estradiol and, to a greater extent, through insulin.

IMPACT

The findings provide support for evaluation of interventions to lower insulin and estrogen levels in overweight and obese postmenopausal women to reduce breast cancer risk.

Annual Report to the Nation on the status of cancer, 1975-2008, featuring cancers associated with excess weight and lack of sufficient physical activity

BACKGROUND

Annual updates on cancer occurrence and trends in the United States are provided through collaboration between the American Cancer Society (ACS), the Centers for Disease Control and Prevention (CDC), the National Cancer Institute (NCI), and the North American Association of Central Cancer Registries (NAACCR). This year's report highlights the increased cancer risk associated with excess weight (overweight or obesity) and lack of sufficient physical activity (<150 minutes of physical activity per week).

METHODS

Data on cancer incidence were obtained from the CDC, NCI, and NAACCR; data on cancer deaths were obtained from the CDC's National Center for Health Statistics. Annual percent changes in incidence and death rates (age-standardized to the 2000 US population) for all cancers combined and for the leading cancers among men and among women were estimated by joinpoint analysis of long-term trends (incidence for 1992-2008 and mortality for 1975-2008) and short-term trends (1999-2008). Information was obtained from national surveys about the proportion of US children, adolescents, and adults who are overweight, obese, insufficiently physically active, or physically inactive.

RESULTS

Death rates from all cancers combined decreased from 1999 to 2008, continuing a decline that began in the early 1990s, among men and among women in most racial and ethnic groups. Death rates decreased from 1999 to 2008 for most cancer sites, including the 4 most common cancers (lung, colorectum, breast, and prostate). The incidence of prostate and colorectal cancers also decreased from 1999 to 2008. Lung cancer incidence declined from 1999 to 2008 among men and from 2004 to 2008 among women. Breast cancer incidence decreased from 1999 to 2004 but was stable from 2004 to 2008. Incidence increased for several cancers, including pancreas, kidney, and adenocarcinoma of the esophagus, which are associated with excess weight.

CONCLUSIONS

Although improvements are reported in the US cancer burden, excess weight and lack of sufficient physical activity contribute to the increased incidence of many cancers, adversely affect quality of life for cancer survivors, and may worsen prognosis for several cancers. The current report highlights the importance of efforts to promote healthy weight and sufficient physical activity in reducing the cancer burden in the United States.

Annual Report to the Nation on the status of cancer, 1975-2008, featuring cancers associated with excess weight and lack of sufficient physical activity

BACKGROUND

Annual updates on cancer occurrence and trends in the United States are provided through collaboration between the American Cancer Society (ACS), the Centers for Disease Control and Prevention (CDC), the National Cancer Institute (NCI), and the North American Association of Central Cancer Registries (NAACCR). This year's report highlights the increased cancer risk associated with excess weight (overweight or obesity) and lack of sufficient physical activity (<150 minutes of physical activity per week).

METHODS

Data on cancer incidence were obtained from the CDC, NCI, and NAACCR; data on cancer deaths were obtained from the CDC's National Center for Health Statistics. Annual percent changes in incidence and death rates (age-standardized to the 2000 US population) for all cancers combined and for the leading cancers among men and among women were estimated by joinpoint analysis of long-term trends (incidence for 1992-2008 and mortality for 1975-2008) and short-term trends (1999-2008). Information was obtained from national surveys about the proportion of US children, adolescents, and adults who are overweight, obese, insufficiently physically active, or physically inactive.

RESULTS

Death rates from all cancers combined decreased from 1999 to 2008, continuing a decline that began in the early 1990s, among men and among women in most racial and ethnic groups. Death rates decreased from 1999 to 2008 for most cancer sites, including the 4 most common cancers (lung, colorectum, breast, and prostate). The incidence of prostate and colorectal cancers also decreased from 1999 to 2008. Lung cancer incidence declined from 1999 to 2008 among men and from 2004 to 2008 among women. Breast cancer incidence decreased from 1999 to 2004 but was stable from 2004 to 2008. Incidence increased for several cancers, including pancreas, kidney, and adenocarcinoma of the esophagus, which are associated with excess weight.

CONCLUSIONS

Although improvements are reported in the US cancer burden, excess weight and lack of sufficient physical activity contribute to the increased incidence of many cancers, adversely affect quality of life for cancer survivors, and may worsen prognosis for several cancers. The current report highlights the importance of efforts to promote healthy weight and sufficient physical activity in reducing the cancer burden in the United States.

Annual Report to the Nation on the status of cancer, 1975-2008, featuring cancers associated with excess weight and lack of sufficient physical activity

BACKGROUND

Annual updates on cancer occurrence and trends in the United States are provided through collaboration between the American Cancer Society (ACS), the Centers for Disease Control and Prevention (CDC), the National Cancer Institute (NCI), and the North American Association of Central Cancer Registries (NAACCR). This year's report highlights the increased cancer risk associated with excess weight (overweight or obesity) and lack of sufficient physical activity (<150 minutes of physical activity per week).

METHODS

Data on cancer incidence were obtained from the CDC, NCI, and NAACCR; data on cancer deaths were obtained from the CDC's National Center for Health Statistics. Annual percent changes in incidence and death rates (age-standardized to the 2000 US population) for all cancers combined and for the leading cancers among men and among women were estimated by joinpoint analysis of long-term trends (incidence for 1992-2008 and mortality for 1975-2008) and short-term trends (1999-2008). Information was obtained from national surveys about the proportion of US children, adolescents, and adults who are overweight, obese, insufficiently physically active, or physically inactive.

RESULTS

Death rates from all cancers combined decreased from 1999 to 2008, continuing a decline that began in the early 1990s, among men and among women in most racial and ethnic groups. Death rates decreased from 1999 to 2008 for most cancer sites, including the 4 most common cancers (lung, colorectum, breast, and prostate). The incidence of prostate and colorectal cancers also decreased from 1999 to 2008. Lung cancer incidence declined from 1999 to 2008 among men and from 2004 to 2008 among women. Breast cancer incidence decreased from 1999 to 2004 but was stable from 2004 to 2008. Incidence increased for several cancers, including pancreas, kidney, and adenocarcinoma of the esophagus, which are associated with excess weight.

CONCLUSIONS

Although improvements are reported in the US cancer burden, excess weight and lack of sufficient physical activity contribute to the increased incidence of many cancers, adversely affect quality of life for cancer survivors, and may worsen prognosis for several cancers. The current report highlights the importance of efforts to promote healthy weight and sufficient physical activity in reducing the cancer burden in the United States.

Dietary intake of folate and alcohol, MTHFR C677T polymorphism, and colorectal cancer risk in Korea

BACKGROUND

The incidence of colorectal cancer (CRC) is increasing sharply in Korea, and evidence has suggested the role of dietary methyl supply and related polymorphisms on colorectal carcinogenesis.

OBJECTIVE

We investigated the association between folate and alcohol intake, methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism, and CRC risk in Koreans.

DESIGN

A total of 787 cases and 656 controls were recruited from 2 university hospitals. Multiple logistic regression models were used to estimate ORs and corresponding 95% CIs.

RESULTS

MTHFR 677T homozygotes were at a lower risk of CRC (OR: 0.60; 95% CI: 0.46, 0.78 for TT compared with CC/CT). High folate intake was associated with reduced CRC risk (OR: 0.64; 95% CI: 0.49, 0.84 for high compared with low intake), and high alcohol consumption was associated with increased risk of CRC (OR: 1.76; 95% CI: 1.26, 2.46 for high compared with low intake). When data were stratified by the amount of dietary methyl (combined intake of folate and alcohol), those with low-methyl diets had higher risk of CRC (OR: 2.32; 95% CI: 1.18, 4.56) than did those with high-methyl diets among CC/CT carriers, whereas the amount of dietary methyl did not affect the CRC risk among carriers with the TT homozygous variant. This association was stronger in patients with colon cancer than in patients with rectal cancer.

CONCLUSION

We found that the effect of dietary methyl supply on colorectal carcinogenesis may differ according to MTHFR C677T genotype and the subsite of origin in a Korean population.

Cigarette experimentation in Mexican origin youth: psychosocial and genetic determinants

BACKGROUND

Established psychosocial risk factors increase the risk for experimentation among Mexican origin youth. Now, we comprehensively investigate the added contribution of select polymorphisms in candidate genetic pathways associated with sensation seeking, risk taking, and smoking phenotypes to predict experimentation.

METHODS

Participants (N = 1,118 Mexican origin youth) recruited from a large population-based cohort study in Houston, TX, provided prospective data on cigarette experimentation over 3 years. Psychosocial data were elicited twice-baseline and final follow-up. Participants were genotyped for 672 functional and tagging variants in the dopamine, serotonin, and opioid pathways.

RESULTS

After adjusting for gender and age, with a Bayesian False Discovery Probability set at 0.8 and prior probability of 0.05, six gene variants were significantly associated with risk of experimentation. After controlling for established risk factors, multivariable analyses revealed that participants with six or more risk alleles were 2.25 [95% confidence interval (CI), 1.62-3.13] times more likely to have experimented since baseline than participants with five or fewer. Among committed never-smokers (N = 872), three genes (OPRM1, SNAP25, HTR1B) were associated with experimentation as were all psychosocial factors. Among susceptible youth (N = 246), older age at baseline, living with a smoker, and three different genes (HTR2A, DRD2, SLC6A3) predicted experimentation.

CONCLUSIONS

Our findings, which have implications for development of culturally specific interventions, need to be validated in other ethnic groups.

IMPACT

These results suggest that variations in select genes interact with a cognitive predisposition toward smoking. In susceptible adolescents, the impact of the genetic variants appears to be larger than committed never-smokers.

Trends in body fat, body mass index and physical fitness among male and female college students

There have been many publications in recent years reporting on the quantity of physical activity among college students using indirect indicators such as steps walked per day or time spent on physical activities. The purpose of this study was to describe the trends of physical fitness related to BMI and body fat among university students between 1996 and 2008. The results showed a significant decline in the average fitness levels measured as an estimation of VO_2max for male and female students (p < 0.001 for both sexes). The linear trend for BMI by years was not significant for both sexes (p for males = 0.772, p for females = 0.253). On average, in the last 13 years, % body fat was increasing 0.513%/year for males and 0.654%/year for females. There is a significant indirect correlation between the student’s VO_2max levels and % body fat, r = −0.489; p < 0.001 for males; and r = −0.416, p < 0.001 for females. Approximately 23.9% of the variance in the VO_2max levels in males and 17.3% in females can be explained by the variance in % body fat. The results support recent findings that physical fitness among college students is declining and body fatness is increasing.

Silibinin suppresses growth of human colorectal carcinoma SW480 cells in culture and xenograft through down-regulation of beta-catenin-dependent signaling

Mutations in APC/beta-catenin resulting in an aberrant activation of Wnt/beta-catenin pathway are common in colorectal cancer (CRC), suggesting that targeting the beta-catenin pathway with chemopreventive/anticancer agents could be a potential translational approach to control CRC. Using human CRC cell lines harboring mutant (SW480) versus wildtype (HCT116) APC gene and alteration in beta-catenin pathway, herein we performed both in vitro and in vivo studies to examine for the first time whether silibinin targets beta-catenin pathway in its efficacy against CRC. Silibinin treatment inhibited cell growth, induced cell death, and decreased nuclear and cytoplasmic levels of beta-catenin in SW480 but not in HCT116 cells, suggesting its selective effect on the beta-catenin pathway and associated biologic responses. Other studies, therefore, were performed only in SW480 cells where silibinin significantly decreased beta-catenin-dependent T-cell factor-4 (TCF-4) transcriptional activity and protein expression of beta-catenin target genes such as c-Myc and cyclin D1. Silibinin also decreased cyclin-dependent kinase 8 (CDK8), a CRC oncoprotein that positively regulates beta-catenin activity, and cyclin C expression. In a SW480 tumor xenograft study, 100- and 200-mg/kg doses of silibinin feeding for 6 weeks inhibited tumor growth by 26% to 46% (P < .001). Analyses of xenografts showed that similar to cell culture findings, silibinin decreases proliferation and expression of beta-catenin, cyclin D1, c-Myc, and CDK8 but induces apoptosis in vivo. Together, these findings suggest that silibinin inhibits the growth of SW480 tumors carrying the mutant APC gene by down-regulating CDK8 and beta-catenin signaling and, therefore, could be an effective agent against CRC.

Breast and ovarian cancer risk evaluation in families with a disease-causing mutation in BRCA1/2

Germline mutations in BRCA1 and BRCA2 confer high risks of breast and ovarian cancer, and their identification allows genetic testing of at-risk relatives. However, estimates of these risks illustrate controversies, depending on the published series. The penetrance, the earlier onset of the disease and the effect of mutations on the risk of developing breast and ovarian cancer were evaluated in 344 females belonging to 34 families from the Basque Country in Spain, in which BRCA1 or BRCA2 mutations were transmitted. Kaplan-Meier survival curves were used to derive cumulative probability curves for breast and ovarian cancer by mutation status, birth cohort and mutation position, and significance of the differences was assessed using the log-rank test. The estimated probability for breast cancer by age 70 is about 64% in BRCA1 and 69% in BRCA2, whereas the probability of developing ovarian cancer is about 37% and 25% for BRCA1 and BRCA2, respectively. There is a marginally significant higher risk of developing ovarian cancer in BRCA1 families than in BRCA2 families. The effect of birth cohort on breast cancer cumulative incidence presents an increased risk for females born after 1966 and a decreased risk for those born before 1940. There is no association between mutation position and breast cancer; however, ovarian cancer is associated to BRCA1, presenting exon 11 as an ovarian cluster. These results are important for the breast and ovarian cancer diagnosis and prevention in at-risk families.

The mediating effect of childhood abuse in sexual orientation disparities in tobacco and alcohol use during adolescence: results from the Nurses' Health Study II

OBJECTIVE

To examine the mediating effect of childhood abuse on sexual orientation disparities in tobacco and alcohol use during adolescence.

METHODS

We carried out analyses with data from over 62,000 women in the ongoing Nurses' Health Study II cohort who provided information on sexual orientation, childhood abuse occurring by age 11, and tobacco and alcohol use in adolescence. We used multivariate regression analyses, controlling for confounders, to estimate the mediating effect of childhood abuse on the association between sexual orientation and tobacco and alcohol use in adolescence.

RESULTS

Lesbian and bisexual orientation and childhood abuse were positively associated with greater risk of tobacco and alcohol use during adolescence. For lesbians, the estimated proportion of excess tobacco and alcohol use in adolescence relative to use among heterosexual women that was mediated by abuse in childhood ranged from 7 to 18%; for bisexual women, the estimated proportion of excess use mediated by abuse ranged from 6 to 13%.

CONCLUSIONS

Elevated childhood abuse in lesbian and bisexual women partially mediated excess tobacco and alcohol use in adolescence relative to heterosexual women. Interventions to prevent child abuse may reduce sexual orientation disparities in some of the leading causes of cancer in women.

Lifestyle as risk factor for cancer: Evidence from human studies

It is increasingly appreciated that the chances of developing cancer are significantly affected by the choice of our lifestyle. There are several uncontrollable risk factors which account for the majority of cancers, but we can modify our lifestyle to reduce enhanced threat of cancer. Healthy lifestyle behaviors for cancer risk reduction include a healthy diet, weight management, regular exercise, reduction in alcohol consumption and smoking cessation. In this article, we present evidences on the association between certain lifestyle characteristics and their contribution for developing breast, prostate, lung and colon cancers, using information derived from human studies.

CDK4 IVS4-nt40 AA genotype and obesity-associated tumors/cancer in Italians - a case-control study

Background

Cell cycle checkpoint regulation is crucial for prevention of tumor in mammalian cells. Cyclin-dependant kinase 4 (CDK4) is important in cell cycle regulation, as it controls the G1-S phase of the cell cycle. CDK4 has potential mitogenic properties through phosphorylation of target proteins. We aimed at identifying a role of CDK4 IVS4-nt40 G→A gene variant in benign and/or malignant tumors and in obesity-associated benign and/or malignant tumors in an Italian adult subject dataset.

Methods

We recruited 263 unrelated Italian subjects: 106 subjects had at least one benign tumor and 46 subjects had at least one malignant tumor, while 116 subjects had at least two tumors and/or cancers. We collected BMI data for 90% of them: 186 subjects had a BMI≥30 Kg/m² and 52 subjects had a BMI ≥ 30 Kg/m². We performed statistical power calculations in our datasets. DNA samples were directly sequenced with specific primers for the CDK4 IVS4-nt40 G→A variant. Genotype association tests with disease were performed.

Results

In our study, no significant association of the CDK4 IVS4-nt40 AA genotype with cancer and/or tumors/cancer are/is detected. However, the CDK4 IVS4-nt40 AA genotype is significantly associated with cancer and tumors/cancer in obese patients.

Conclusion

This finding is interesting since obesity is a risk factor for tumors and cancer. This study should prompt further work aiming at establishing the role of CDK4 in contributing to tumor/cancer genetic risk predisposition, as well as its role as a potentially effective therapeutic target gene for obesity-associated tumor/cancer management.